Baffle for damper with electromechanical valve

ABSTRACT

A shock absorber includes a pressure tube forming a working chamber. A reserve tube is concentric with and radially outward from the pressure tube. A baffle is positioned radially outward from the pressure tube. A reservoir chamber is formed between the reserve tube and the baffle. A piston is attached to a piston rod and slidably disposed within the pressure tube. A rod guide is attached to the pressure tube and supports the piston rod. An electromechanical valve is positioned within the rod guide. A plurality of non-linear passageways are disposed between the baffle and at least one of the pressure tube and the reserve tube for transporting fluid between the electromechanical valve and the reservoir chamber.

FIELD

The present disclosure relates generally to hydraulic dampers or shock absorbers for use in a suspension system such as a suspension system used for automotive vehicles. More particularly, the present disclosure relates to a baffle for a damper including an electromechanical valve.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

In general, conventional shock absorbers produce damping force characteristics based on a velocity of a piston rod that translates relative to a body of the shock absorber. The shock absorber includes a valve through which oil flows during movement of the piston rod. A pressure differential is generated within the shock absorber based on the configuration and location of the valve. The working pressures provide a resistive or damping force between the piston rod and the body of the shock absorber to provide a desired damping force characteristic of a vehicle's suspension.

Electronically adjustable shock absorbers are also available. These shock absorbers produce damping force characteristics as well but the damping force is adjustable over a damping force range. As such, electronically-adjustable shock absorbers may provide multiple damping force characteristic curves for the same piston rod velocity.

Both conventional and electronically-adjustable shock absorbers may exhibit a lower magnitude of damping force than desired if an insufficient oil fluid volume is present in the shock absorber reservoir chamber or if the fluid is aerated. Many shock absorbers are configured as twin tube shock absorbers where the reservoir contains both a liquid oil fluid and a pressurized gas within the same chamber. The oil fluid level within the reservoir changes during shock absorber operation but the shock absorber is configured to maintain a minimum oil level at all times. In certain shock absorbers, the physical position of the valves relative to the liquid level in the reservoir may induce a mixing of gas and liquid thereby aerating the liquid oil. A resultant lag of damping force occurs due to the compressibility of the gas within the liquid. It is at least one object of the present disclosure to mitigate aeration of the liquid within the shock absorber to minimize a lag in providing a target damping force.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

A shock absorber includes a pressure tube forming a working chamber. A reserve tube is concentric with and radially outward from the pressure tube. A baffle is positioned radially outward from the pressure tube. A reservoir chamber is formed between the reserve tube and the baffle. A piston is attached to a piston rod and slidably disposed within the pressure tube. A rod guide is attached to the pressure tube and supports the piston rod. An electromechanical valve is positioned within the rod guide. The baffle and the pressure tube form a fluid passage between the electromechanical valve and the reservoir chamber.

The present disclosure also describes a shock absorber including a piston assembly attached to a piston rod and slidably disposed within a pressure tube. The piston assembly divides a working chamber into an upper working chamber and a lower working chamber. The piston assembly includes a first valve assembly controlling fluid flowing through a first fluid passage that connects the upper working chamber with the lower working chamber. A reservoir tube is disposed around the pressure tube. A baffle is positioned radially outward from the pressure tube and at least partially defines a baffle channel between the pressure tube and the baffle. The reservoir chamber is positioned between the baffle and the reserve tube. A second valve is positioned within the pressure tube for controlling fluid flow between one of the upper and lower working chambers and the reservoir chamber. A rod guide supports the piston rod and is attached to an end of the pressure tube. A second fluid passage extends from one of the upper and lower working chambers to the baffle channel. An electromechanical valve is positioned within the rod guide for controlling fluid flow through the second passage. The baffle channel fluidly connects the electromechanical valve and the reservoir.

The present disclosure also describes a shock absorber where a plurality of passageways are disposed between the baffle and the pressure tube. The plurality of passageways are defined by grooves in the baffle and at least one of an outer surface of the pressure tube and an inner surface of the reserve tube. At least one of the plurality of passageways is disposed in fluid communication with the electromechanical valve and the reservoir for transporting fluid from the electromechanical valve to the reservoir chamber with minimal foaming.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is an illustration of an automobile having shock absorbers which incorporate the valve design in accordance with the present disclosure;

FIG. 2 is a side view, partially in cross-section of a dual-tube shock absorber from FIG. 1 which incorporates the valve design in accordance with the present disclosure;

FIG. 3 is an enlarged side view, partially in cross-section of the piston assembly from the shock absorber illustrated in FIG. 2;

FIG. 4 is an enlarged side view, partially in cross-section of the base valve assembly from the shock absorber illustrated in FIG. 2;

FIG. 5 is an enlarged side view, partially in cross-section of the electromechanical valve assembly from the shock absorber illustrated in FIG. 2;

FIG. 6 is an enlarged cross-sectional perspective view of the electromechanical valve assembly illustrated in FIGS. 2 and 5;

FIG. 7 is an enlarged cross-sectional view of the dual-tube shock absorber illustrating fluid pressures and flows during a compression stroke;

FIG. 8 is an enlarged cross-sectional view of the dual-tube shock absorber illustrating fluid pressures and flows during a rebound stroke;

FIG. 9 is a side view, partially in cross-section of another dual-tube shock absorber constructed in accordance with the present disclosure;

FIG. 10 is a side perspective view of the baffle of the dual-tube shock absorber illustrated in FIG. 9;

FIG. 11 is a top cross-sectional view of the baffle of the dual-tube shock absorber illustrated in FIG. 10, which is taken along section line A-A;

FIG. 12 is a side view, partially in cross-section of another dual-tube shock absorber constructed in accordance with the present disclosure;

FIG. 13 is a side cross-sectional view of the baffle of the dual-tube shock absorber illustrated in FIG. 12;

FIG. 14 is a side perspective view of the baffle of the dual-tube shock absorber illustrated in FIG. 12;

FIG. 15 is a top cross-sectional view of the baffle of the dual-tube shock absorber illustrated in FIG. 14, which is taken along section line B-B;

FIG. 16 is a side view, partially in cross-section of another dual-tube shock absorber constructed in accordance with the present disclosure;

FIG. 17 is a side cross-sectional view of the baffle of the dual-tube shock absorber illustrated in FIG. 16;

FIG. 18 is a side perspective view of the baffle of the dual-tube shock absorber illustrated in FIG. 16;

FIG. 19 is a top cross-sectional view of the baffle of the dual-tube shock absorber illustrated in FIG. 18, which is taken along section line C-C;

FIG. 20 is a side view, partially in cross-section of another dual-tube shock absorber constructed in accordance with the present disclosure;

FIG. 21 is a side elevation view of the baffle of the dual-tube shock absorber illustrated in FIG. 20;

FIG. 22 is a side perspective view of the baffle of the dual-tube shock absorber illustrated in FIG. 20; and

FIG. 23 is a top cross-sectional view of the baffle of the dual-tube shock absorber illustrated in FIG. 22, which is taken along section line D-D.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. There is shown in FIG. 1 a vehicle incorporating a suspension system having shock absorbers, each of which incorporates a valve assembly in accordance with the present invention, and which is designated generally by the reference numeral 10. Vehicle 10 includes a rear suspension 12, a front suspension 14 and a body 16.

Rear suspension 12 has a transversely extending rear axle assembly (not shown) adapted to operatively support a pair of rear wheels 18. The rear axle is attached to the body 16 by means of a pair of shock absorbers 20 and by a pair of springs 22. Similarly, front suspension 14 includes a transversely extending front axle assembly (not shown) to operatively support a pair of front wheels 24. The front axle assembly is attached to the body 16 by means of a pair of shock absorbers 26 and by a pair of springs 28.

Shock absorbers 20 and 26 serve to dampen the relative motion of the unsprung portion (i.e., front and rear suspensions 12, 14) with respect to the sprung portion (i.e., body 16) of vehicle 10. While vehicle 10 has been depicted as a passenger car having front and rear axle assemblies, shock absorbers 20 and 26 may be used with other types of vehicles or in other types of applications including, but not limited to, vehicles incorporating non-independent front and/or non-independent rear suspensions, vehicles incorporating independent front and/or independent rear suspensions or other suspension systems known in the art. Further, the term “shock absorber” as used herein is meant to refer to dampers in general and thus will include McPherson struts and other damper designs known in the art.

Referring now to FIG. 2, shock absorber 20 is shown in greater detail. While FIG. 2 illustrates only shock absorber 20, it is to be understood that shock absorber 26 also includes the valve assembly design described below for shock absorber 20. Shock absorber 26 only differs from shock absorber 20 in the manner in which it is adapted to be connected to the sprung and unsprung masses of vehicle 10. Shock absorber 20 comprises a pressure tube 30, a piston assembly 32, a piston rod 34, a reserve tube 36, a base valve assembly 38 and a baffle 40.

Pressure tube 30 defines a working chamber 42. Piston assembly 32 is slidably disposed within pressure tube 30 and divides working chamber 42 into an upper working chamber 44 and a lower working chamber 46. A seal 48 is disposed between piston assembly 32 and pressure tube 30 to permit sliding movement of piston assembly 32 with respect to pressure tube 30 without generating undue frictional forces as well as sealing upper working chamber 44 from lower working chamber 46. Piston rod 34 is attached to piston assembly 32 and extends through upper working chamber 44 and through a rod guide assembly 50. A pressure tube adapter 51 is disposed between the rod guide assembly 50 and the upper end of the pressure tube 30 such that the pressure tube adapter 51 closes the upper end of pressure tube 30. In one non-limiting example, the pressure tube adapter 51 may be press-fit into the upper end of the pressure tube 30 during assembly. A bumper stop 53 positioned adjacent to the pressure tube adapter 51 extends annularly about the piston rod 34. The bumper stop 53 prevents the piston assembly 32 from contacting the pressure tube adapter 51 on the rebound stroke. The end of piston rod 34 opposite to piston assembly 32 is adapted to be secured to the sprung mass of vehicle 10. Valving within piston assembly 32 controls the movement of fluid between upper working chamber 44 and lower working chamber 46 during movement of piston assembly 32 within pressure tube 30. Because piston rod 34 extends only through upper working chamber 44 and not lower working chamber 46, movement of piston assembly 32 with respect to pressure tube 30 causes a difference in the amount of fluid displaced in upper working chamber 44 and the amount of fluid displaced in lower working chamber 46. The difference in the amount of fluid displaced is known as the “rod volume” and it flows through base valve assembly 38.

Reserve tube 36 surrounds pressure tube 30 to define a fluid reservoir chamber 52 located between the pressure tube 30 and the reserve tube 36. The bottom end of reserve tube 36 is closed by a base cup 54 which is adapted to be connected to the unsprung mass of vehicle 10. The upper end of reserve tube 36 is attached to rod guide assembly 50. Base valve assembly 38 is disposed between lower working chamber 46 and reservoir chamber 52 to control the flow of fluid between chambers 46 and 52. When shock absorber 20 extends in length, an additional volume of fluid is needed in lower working chamber 46 due to the “rod volume” concept. Thus, fluid will flow from reservoir chamber 52 to lower working chamber 46 through base valve assembly 38 as detailed below. When shock absorber 20 compresses in length, an excess of fluid must be removed from lower working chamber 46 due to the “rod volume” concept. Thus, fluid will flow from lower working chamber 46 to reservoir chamber 52 through base valve assembly 38 as detailed below.

Baffle 40 extends concentrically between pressure tube 30 and reserve tube 36. An upper end of baffle 40 is attached to rod guide assembly 50. An attachment mechanism 55 may include a hook, a snap-fit, a press fit or another suitable arrangement. In addition, the upper end of the baffle 40 includes a collar 57 that extends radially outwardly. The reserve tube 36 has a transition 59 where the diameter of the reserve tube 36 decreases. The collar 57 of the baffle 40 contacts the transition 59 of the reserve tube 36 to lock the baffle 40 in place and prevent the baffle 40 from moving axially relative to the reserve tube 36 and the rod guide assembly 50. Alternatively, the baffle 40 may be press-fit into the reserve tube 36 or welded to the reserve tube 36. A lower distal end of baffle 40 is shown unsupported and spaced apart from pressure tube 30, reserve tube 36 and base valve assembly 38. Alternatively, a support structure may be connected to the lower distal end of the baffle. The lower distal end of baffle 40 extends into reservoir chamber 52 to such an extent to assure that the end maintains continuous contact with liquid fluid positioned within reservoir chamber 52. More particularly, a baffle channel 56 exists between an outer cylindrical surface of pressure tube 30 and an inner cylindrical surface of baffle 40. This annular space is completely filled with liquid at all times of operation of shock absorber 20.

A portion of reservoir chamber 52 positioned between an outer cylindrical surface of baffle 40 and an internal cylindrical surface of reserve tube 36 contains liquid fluid such as an oil in the lower region that at least includes the distal lower end of baffle 40. A pressurized gas is positioned within an upper portion of reservoir chamber 52. An o-ring 58 disposed along the collar 57 of the baffle 40 seals the upper end of baffle 40 to reserve tube 36. Other structures useful for providing sealing attachment, including a press fit or a weld, are contemplated as being within the scope of the present disclosure.

Referring now to FIG. 3, piston assembly 32 comprises a piston body 60, a compression valve assembly 62 and a rebound valve assembly 64. Compression valve assembly 62 is assembled against a shoulder 66 on piston rod 34. Piston body 60 is assembled against compression valve assembly 62 and rebound valve assembly 64 is assembled against piston body 60. A nut 68 secures these components to piston rod 34.

Piston body 60 defines a plurality of compression passages 70 and a plurality of rebound passages 72. Seal 48 includes a plurality of ribs 74 which mate with a plurality of annular grooves 76 to retain seal 48 during sliding movement of piston assembly 32.

Compression valve assembly 62 comprises a retainer 78, a valve disc 80 and a spring 82. Retainer 78 abuts shoulder 66 on one end and piston body 60 on the other end. Valve disc 80 abuts piston body 60 and closes compression passages 70 while leaving rebound passages 72 open. Spring 82 is disposed between retainer 78 and valve disc 80 to bias valve disc 80 against piston body 60. During a compression stroke, fluid in lower working chamber 46 is pressurized causing fluid pressure to react against valve disc 80. When the fluid pressure against valve disc 80 overcomes the biasing load of spring 82, valve disc 80 separates from piston body 60 to open compression passages 70 and allow fluid flow from lower working chamber 46 to upper working chamber 44. Typically spring 82 only exerts a light load on valve disc 80 and compression valve assembly 62 acts as a check valve between chambers 46 and 44. The damping characteristics for shock absorber 20 during a compression stroke are controlled in part by base valve assembly 38 which accommodates the flow of fluid from lower working chamber 46 to reservoir chamber 52 due to the “rod volume” concept. During a rebound stroke, compression passages 70 are closed by valve disc 80.

Rebound valve assembly 64 is termed a passive valve assembly which comprises a spacer 84, a plurality of valve discs 86, a retainer 88 and a spring 90. Spacer 84 is threadingly received on piston rod 34 and is disposed between piston body 60 and nut 68. Spacer 84 retains piston body 60 and compression valve assembly 62 while permitting the tightening of nut 68 without compressing either valve disc 80 or valve discs 86. Retainer 78, piston body 60 and spacer 84 provide a continuous solid connection between shoulder 66 and nut 68 to facilitate the tightening and securing of nut 68 to spacer 84 and thus to piston rod 34. Valve discs 86 are slidingly received on spacer 84 and abut piston body 60 to close rebound passages 72 while leaving compression passages 70 open. Retainer 88 is also slidingly received on spacer 84 and it abuts valve discs 86. Spring 90 is assembled over spacer 84 and is disposed between retainer 88 and nut 68 which is threadingly received on spacer 84. Spring 90 biases retainer 88 against valve discs 86 and valve discs 86 against piston body 60. When fluid pressure is applied to valve discs 86, they will elastically deflect at the outer peripheral edge to open rebound valve assembly 64. A shim is located between nut 68 and spring 90 to control the preload for spring 90 and thus the blow off pressure as described below. Thus, the calibration for the blow off feature of rebound valve assembly 64 is separate from the calibration for compression valve assembly 62.

During a rebound stroke, fluid in upper working chamber 44 is pressurized causing fluid pressure to react against valve discs 86. Prior to the deflecting of valve discs 86, a bleed flow of fluid flows through a bleed passage defined between valve discs 86 and piston body 60. When the fluid pressure reacting against valve discs 86 overcomes the bending load for valve discs 86, valve discs 86 elastically deflect opening rebound passages 72 allowing fluid flow from upper working chamber 44 to lower working chamber 46. The strength of valve discs 86 and the size of rebound passages will determine the damping characteristics for shock absorber 20 in rebound. When the fluid pressure within upper working chamber 44 reaches a predetermined level, the fluid pressure will overcome the biasing load of spring 90 causing axial movement of retainer 88 and the plurality of valve discs 86. The axial movement of retainer 88 and valve discs 86 fully opens rebound passages 72 thus allowing the passage of a significant amount of damping fluid thereby creating a blowing off of the fluid pressure which is required to prevent damage to shock absorber 20 and/or vehicle 10.

Referring to FIG. 4, base valve assembly 38 comprises a valve body 92, a compression valve assembly 94 and a rebound valve assembly 96. Compression valve assembly 94 and rebound valve assembly 96 are attached to valve body 92 using a bolt 98 and a nut 100. The tightening of nut 100 biases compression valve assembly 94 towards valve body 92. Valve body 92 defines a plurality of compression passages 102 and a plurality of rebound passages 104.

Compression valve assembly 94 is termed a passive valve assembly which comprises a plurality of valve discs 106 that are biased against valve body 92 by bolt 98 and nut 100. During a compression stroke, fluid in lower working chamber 46 is pressurized and the fluid pressure within compression passages 102 reacts against valve discs 106. Prior to the deflection of valve discs 106, a bleed flow of fluid will flow through a bleed passage defined between valve discs 106 and valve body 92. The fluid pressure reacting against valve discs 106 will eventually open compression valve assembly 94 by deflecting valve discs 106 in a manner similar to that described above for rebound valve assembly 64. Compression valve assembly 62 will allow fluid flow from lower working chamber 46 to upper working chamber 44 and only the “rod volume” will flow through compression valve assembly 94. The damping characteristics for shock absorber 20 are determined in part by the design of compression valve assembly 94 of base valve assembly 38.

Rebound valve assembly 96 comprises a valve disc 108 and a valve spring 110. Valve disc 108 abuts valve body 92 and closes rebound passages 104. Valve spring 110 is disposed between nut 100 and valve disc 80 to bias valve disc 108 against valve body 92. During a rebound stroke, fluid in lower working chamber 46 is reduced in pressure causing fluid pressure in reservoir chamber 52 to react against valve disc 108. When the fluid pressure against valve disc 108 overcomes the biasing load of valve spring 110, valve disc 108 separates from valve body 92 to open rebound passages 104 and allow fluid flow from reservoir chamber 52 to lower working chamber 46. Typically valve spring 110 exerts only a light load on valve disc 108 and compression valve assembly 94 acts as a check valve between reservoir chamber 52 and lower working chamber 46. The damping characteristics for a rebound stroke are controlled in part by rebound valve assembly 64 as detailed above.

Referring now to FIGS. 5 and 6, rod guide assembly 50 is illustrated in greater detail. Rod guide assembly 50 comprises a rod guide housing 120, a seal assembly 122, and an electromechanical valve assembly 126.

Rod guide housing 120 is assembled into pressure tube 30 and into reserve tube 36. The rod guide housing 120 includes one or more depressions 121 that are formed in the outer surface of the rod guide housing 120. The upper end of the reserve tube 36 is crimped or formed into the depressions 121 in the rod guide housing 120 to lock the rod guide housing 120 in place and prevent the rod guide housing 120 from moving longitudinally relative to the reserve tube 36. Seal assembly 122 is assembled to rod guide housing 120. A cap 128 is attached to the end of shock absorber 20. A bushing 130 assembled into rod guide housing 120 accommodates for the sliding motion of piston rod 34 while also providing for a seal for piston rod 34. A fluid passage 132 extends through rod guide housing 120 to allow fluid communication between upper working chamber 44 and electromechanical valve assembly 126 as discussed below.

Electromechanical valve assembly 126 is a two position valve assembly which has a different flow area in each of the two positions. Electromechanical valve assembly 126 comprises a valve housing 140, a sleeve 142, a spool 144, a spring 146 and a coil assembly 148. It should be appreciated that valve housing 140 may be integral to rod guide housing 120. Valve housing 140 defines a valve inlet 150 which is in communication with upper working chamber 44 through fluid passage 132 and a valve outlet 152 which is in fluid communication with baffle channel 56. At least part of the valve outlet 152 is defined by a chamfer 153 in the pressure tube adapter 51. Fluid exits the electromechanical valve assembly 126 moving in an axial direction. The chamfer 153 of the pressure tube adapter 51 changes the fluid flow exiting the electromechanical valve assembly 126 to a radial direction. The fluid flow then turns again back to a longitudinal direction as it flows through the baffle channel 56. This non-linear, tortuous fluid flow path through the valve outlet 152 reduces foaming of the fluid in the valve outlet 152. It should be appreciated that the chamfer 153 of the pressure tube adapter 51 may be replaced by other structures. By way of example and without limitation, the chamfer 153 of the pressure tube adapter 51 may be replaced by a radially extending channel in the pressure tube adapter 51. While this embodiment and other embodiments described later include spring 146 in the electromechanical valve assemblies, it is within the scope of the present disclosure to use electromechanical valve assemblies that do not include spring 146. Electromechanical valve assemblies that do not include spring 146 are moved between their two positions by reversing the current or reversing the polarity of the power provided to the electromechanical valve assembly. It is also contemplated that other electromechanical valves may be implemented into the shock absorber of the present disclosure. For example, a suitable alternative valve may include a side inlet and a bottom outlet.

Sleeve 142 is disposed within valve housing 140. Sleeve 142 defines an annular inlet chamber 154 which is in communication with valve inlet 150 and a pair of annular outlet chambers 156 and 158 which are in communication with valve outlet 152. It should be appreciated that alternate configurations having only one outlet are within the scope of the present disclosure. The outlet(s) may be directed axially instead of the radial orientation depicted.

Spool 144 is slidingly received within sleeve 142 and axially travels within sleeve 142 between coil assembly 148 and a stop puck 160 disposed within sleeve 142. Spring 146 biases spool 144 away from coil assembly 148 and towards stop puck 160. A shim 162 is disposed between coil assembly 148 and sleeve 142 to control the amount of axial motion for spool 144. A first O-ring seals the interface between stop puck 160, sleeve 142 and valve housing 140. A second O-ring seals the interface between coil assembly 148, sleeve 142 and rod guide housing 120.

Spool 144 defines a first flange 164 which controls fluid flow between annular inlet chamber 154 and annular outlet chamber 156 and a second flange 166 that controls fluid flow between annular inlet chamber 154 and annular outlet chamber 158. Flanges 164 and 166 thus control fluid flow from upper working chamber 44 to reservoir chamber 52. The number of flanges depends on the configuration of the outlet. One or more flanges may be used.

Coil assembly 148 is disposed within sleeve 142 to control the axial movement of spool 144. The wiring connections for coil assembly 148 can extend through rod guide housing 120, through sleeve 142, through valve housing 140 and/or through reserve tube 36. When there is no power provided to coil assembly 148, the damping characteristics will be defined by the flow area of electromechanical valve assembly 126 in its first position, piston assembly 32 and base valve assembly 38. The movement of spool 144 is controlled by supplying power to coil assembly 148 to move electromechanical valve assembly 126 to its second position. Electromechanical valve assembly 126 can be kept in its second position by continuing to supply power to coil assembly 148 or by providing means for retaining electromechanical valve assembly 126 in its second position and discontinuing the supply of power to coil assembly 148. The means for retaining electromechanical valve assembly 126 in its second position can include mechanical means, magnetic means or other means known in the art. Once in its second position, movement to the first position can be accomplished by terminating power to coil assembly 148 or by reversing the current or reversing the polarity of the power supplied to coil assembly 148 to overcome the retaining means. The amount of flow through electromechanical valve assembly 126 has discrete settings for flow control in both the first position and the second position.

While the present disclosure is described using only one electromechanical valve assembly 126, it is within the scope of the disclosure to use a plurality of electromechanical valve assemblies 126. When multiple electromechanical valve assemblies 126 are used, the total flow area through the plurality of electromechanical valve assemblies 126 can be set at a specific number of total flow areas depending on the position of each individual electromechanical valve assembly 126. The specific number of total flow areas can be defined as being 2^(n) flow areas where n is the number of electromechanical valve assemblies 126. For example, if there are four electromechanical valve assemblies 126, the number of total flow areas available would be 2⁴ or sixteen flow areas.

Referring to FIG. 7, the working principles of shock absorber 20 during a compression stroke are depicted. A compression stroke includes advancing piston rod 34 into pressure tube 30. As piston rod 34 is translated, it enters pressure tube 30 and displaces a volume of oil equal to the rod volume. A primary oil flow Q1 passes through the restrictions in base valve assembly 38. At the same time, an annular volume Q1′ flows in an unrestricted manner through compression valve assembly 62 to replenish the volume of oil within upper working chamber 44. If one or more of electromechanical valve assemblies 126 are in an OPEN state, then a secondary oil flow Q2 occurs in parallel with the primary oil flow Q1. The secondary oil flow(s) Q2 are restricted by orifice areas associated with each of electromechanical valve assemblies 126.

As a result of the flows Q1 and Q2, a high pressure P1 occurs within lower working chamber 46 of pressure tube 30 between base valve assembly 38 and piston assembly 32. A lower pressure P2′ occurs below the base valve assembly 38 due to the pressure differential (P1>P2′). A lower pressure occurs above the piston assembly 32 due to the pressure differential (P1>P1′). Likewise, a lower pressure P2″ occurs after the orifice restrictions associated with each electromechanical valve assembly 126 due to the pressure differential (P1′>P2″). Additional pressure differentials may be associated with each electromechanical valve assembly 126 if there are any internal flow restrictions within the electromechanical valve assemblies 126, in which case a lower pressure P3″ occurs after electromechanical valve assemblies 126 due to the pressure differential (P2″>P3″).

The secondary oil flow Q2 continues within baffle channel 56 and rejoins the primary oil flow Q1 in reservoir chamber 52 in order for Qtotal=(Q1+Q2). A pressure P3′ at the bottom of baffle 40 and after base valve assembly 38 will be equal to the gas charge pressure Pg in reservoir chamber 52 (i.e., P3″>P3′=Pg).

Referring to FIG. 8, during a rebound stroke (or extension stroke) of the shock absorber, piston rod 34 exits from pressure tube 30 and displaces a volume of oil equal to the rod volume. The primary oil flow Q1 passes through the restrictions in piston assembly 32. At the same time, rod volume Q1′ flows unrestricted through base valve assembly 38 to replenish the volume of oil within the lower portion of pressure tube 30 between piston assembly 32 and base valve assembly 38. If one or more electromechanical valve assemblies 126 are in the OPEN state, then a secondary oil flow Q2 occurs in parallel with the primary oil flow Q1. The secondary oil flow(s) Q2 are restricted by orifice areas associated with each of the electromechanical valve assemblies 126.

As a result of the flows Q1 and Q2, high pressure P1 occurs within the working chamber of pressure tube 30 between piston assembly 32 and rod guide assembly 50. A lower pressure P1′ occurs below piston assembly 32 due to the pressure differential (P1>P1′) and (P2′>P1′). Likewise, a lower pressure P2″ occurs after the orifice restrictions associated with each electromechanical valve assembly 126 due to the pressure differential (P1>P2″). There may be additional pressure differentials associated with each electromechanical valve assembly 126 if there are any internal flow restrictions within electromechanical valve assemblies 126. In which case, a lower pressure P3″ occurs after electromechanical valve assemblies 126 due to the pressure differential (P2″>P3″).

The secondary oil flow Q2 continues within the baffle channel 56 and rejoins the primary oil flow Q1 in the reservoir chamber 52 in order for Qtotal=(Q1+Q2). The pressure P3′ at the bottom of baffle 40 and after base valve assembly 38 will be equal to the gas charge pressure Pg in the reservoir chamber 52 (i.e., P3″>P3′=Pg).

Since baffle 40 is sealed at the upper end by O-ring 58 or another sealing method, the pressure at the upper end of baffle 40 is always higher than the pressure at the lower end of baffle 40 within reservoir chamber 52 (i.e., P3″>P3′=Pg). The oil level within reservoir chamber 52 is defined to always remain above the lower end of baffle 40 during total stroke of the shock absorber from extension to compression. As a result, baffle 40 mitigates the risk for aeration or lag in damping force since P1>P2″>P3″>P3′=Pg and Qtotal=(Q1+Q2).

While not shown here with an illustration, another embodiment of the disclosure includes individual baffles for each electromechanical valve assembly 126. This embodiment would function in the same manner as described previously. The only difference is packaging of the baffles. The individual baffles would have a defined diameter to allow sufficient oil flow rate Q2 (for example, 8 mm inside diameter). Each baffle would be sealed at the outlet of each electromechanical valve assembly 126 using an elastomeric seal, press fit, weld, or other means known in the art. Similarly, the oil level within the reservoir chamber 52 would be defined to always remain above the lower end of the baffles during total stroke of the shock absorber from extension to compression. As a result, the baffles will mitigate the risk for aeration or lag in damping force since P1>P2″>P3″>P3′=Pg and Qtotal=(Q1+Q2).

FIGS. 9-11 illustrate another alternative embodiment where the shock absorber 20 includes a baffle 240 with a plurality of grooves 242 a, 242 b, 242 c, 242 d that extend helically along an outer surface 246 of the baffle 240. In the illustrated embodiment, the plurality of grooves 242 a, 242 b, 242 c, 242 d extend from an upper end 254 of the baffle 240 to a lower end 255 of the baffle 240; however, the plurality of grooves 242 a, 242 b, 242 c, 242 d may alternatively extend along only a part of the longitudinal length of the baffle 240. As shown in FIGS. 9-11, the baffle 240 extends annularly about the pressure tube 30 and is disposed radially between the pressure tube 30 and the reserve tube 36. However, it should be appreciated that the baffle 240 may alternatively extend less than 360 degrees about the pressure tube 30. For example, the baffle 240 may include a separation (i.e. a gap) that extends longitudinally from the upper end 254 to the lower end 255 of the baffle 240. In another alternative embodiment, the baffle 240 may include multiple separations that break the baffle 240 up into discrete sections that extend radially about only a portion of the pressure tube 30.

In the illustrated embodiment, an inner surface 244 of the baffle 240 is a smooth cylindrical surface and is arranged in contact with the outer cylindrical surface of the pressure tube 30 to support the baffle 240 concentrically on the pressure tube 30. Alternatively, the inner surface 244 of the baffle 240 may be spaced radially outward of the outer cylindrical surface of the pressure tube 30 and the baffle 240 may be supported by the reserve tube 36.

Together, grooves 242 a and 242 c define a baffle channel 256 in the form of a first helical passageway 258 a and a third helical passageway 258 c. In the illustrated embodiment, the first and third helical passageways 258 a, 258 c extend from the upper end 254 of the baffle 240 to the lower end 255 of the baffle 240 and radially between the inner cylindrical surface of the reserve tube 36 and the outer surface 246 of the baffle 240 in grooves 242 a and 242 c. However, it should be appreciated that the first and third helical passageways 258 a, 258 c may extend along only part of the longitudinal length of the baffle 240. A reservoir chamber 252 is disposed between the pressure tube 30 and the reserve tube 36 adjacent to the lower end 255 of the baffle 240. Grooves 242 b and 242 d are disposed in fluid communication with the reservoir chamber 252 only. In other words, the grooves 242 b and 242 d are open to the reservoir chamber 252 at the lower end 255 of the baffle 240 and are closed at the upper end 254 of the baffle 240. Accordingly, grooves 242 b and 242 d also define part of the reservoir chamber 252 in the form of a second helical passageway 258 b and a fourth helical passageway 258 d. A liquid fluid such as an oil is contained in a lower region of the reservoir chamber 252 and a pressurized gas is contained in an upper portion of reservoir chamber 252. In embodiments where the inner surface 244 of the baffle 240 is spaced radially outward of the outer cylindrical surface of the pressure tube 30, the space between the pressure tube 30 and the inner surface 244 of the baffle 240 may also form part of the reservoir chamber 252.

The passageways 258 a, 258 b, 258 c, 258 d are non-linear and provide a tortuous fluid flow path along the outer surface 246 of the baffle 240. Because all of the passageways 258 a, 258 b, 258 c, 258 d have a helical shape, the passageways 258 a, 258 b, 258 c, 258 d have both a longitudinal component and a circumferential component. The plurality of grooves 242 a, 242 b, 242 c, 242 d and therefore the helical passageways 258 a, 258 b, 258 c, 258 d are radially spaced about the baffle 240 such that threads 260 a, 260 b, 260 c, 260 d are formed in the baffle 240 that extend radially outwardly from the baffle 240 between the plurality of grooves 242 a, 242 b, 242 c, 242 d. The outer surface 246 of the baffle 240 at the threads 260 a, 260 b, 260 c, 260 d contacts the inner cylindrical surface of the reserve tube 36 to support the baffle 240 concentrically without the reserve tube 36. Because the outer surface 246 of the baffle 240 at the threads 260 a, 260 b, 260 c, 260 d contacts the inner cylindrical surface of the reserve tube 36, the helical passageways 258 a, 258 b, 258 c, 258 d defined by the plurality of grooves 242 a, 242 b, 242 c, 242 d are separate from one another (i.e., fluid flowing through the first helical passageway 258 a is isolated from fluid flowing through the second helical passageway 258 b along at least part of the longitudinal length of the baffle 240).

In the illustrated embodiment, both the first and third helical passageways 258 a and 258 c are disposed in fluid communication with at least one electromechanical valve assembly 126 and the reservoir chamber 252. Alternatively, the shock absorber 20 may include one electromechanical valve assembly for each of the first and third helical passageways 258 a and 258 c. When the at least one electromechanical valve assembly 126 is in the OPEN state, fluid flows through the first and third helical passageways 258 a and 258 c along flow direction F1. The second and fourth helical passageways 258 b and 258 d are disposed in fluid communication with only the reservoir chamber 252. The second and fourth helical passageways 258 b and 258 d are closed (i.e. not open) to the one or more electromechanical valve assemblies 126. Fluid in the reservoir chamber 252 flows in the opposite direction in the second and fourth helical passageways 258 b and 258 d along flow direction F2. In another embodiment, all four helical passageways 258 a, 258 b, 258 c, 258 d may communicate with one electromechanical valve assemblies 126.

Transfer passages 262 extend through the baffle 240 and are disposed in fluid communication with the valve outlet 152 and the first and third helical passageways 258 a and 258 c. Fluid from the valve outlet 152 flows into the first and third helical passageways 258 a and 258 c and to the reservoir chamber 252. The baffle 240 may optionally include a clocking feature 264 that ensures proper positioning (i.e., indexing) of the baffle 240, where the first and third helical passageways 258 a and 258 c are circumferentially aligned with the valve outlet(s) 152 of the one or more electromechanical valve assemblies 126. By way of example and without limitation, the clocking feature 264 may be provided in the form of a notch in the upper end 254 of the baffle 240 that engages a tab on the rod guide assembly 50. In the illustrated example, the one or more electromechanical valve assemblies 126 are located in the rod guide assembly 50. However, other configurations are possible. For example, the one or more electromechanical valve assemblies 126 may be mounted externally on the reserve tube 36. Even though the one or more electromechanical valve assemblies 126 are external to the reserve tube 36, the inside passages of the one or more electromechanical valve assemblies 126 are disposed in fluid communication with the baffle channel 256 and the reservoir chamber 252. As a result, the one or more electromechanical valve assemblies 126 are operable to control fluid flow from the baffle channel 256 to the reservoir chamber 252.

Advantageously, the first and third helical passageways 258 a and 258 c defined by grooves 242 a and 242 c transport fluid from the valve outlet 152 of the electromechanical valve assembly 126 to the reservoir chamber 252 with minimal foaming (i.e., bubbling). The subject design minimizes the volume of the baffle channel 256. The subject design also maximizes the volume of the reservoir chamber 252 due to the added volume of second and fourth helical passageways 258 b and 258 d. In the example shown in FIGS. 9-11, the plurality of grooves 242 a, 242 b, 242 c, 242 d have a rectangular cross-sectional shape; however, it should be appreciated that other shapes are possible. In addition, it should be appreciated that the number of grooves and therefore the number of helical passageways may vary from the four grooves 242 a, 242 b, 242 c, 242 d and the four helical passageways 258 a, 258 b, 258 c, 258 d shown in the illustrated embodiment.

FIGS. 12-15 illustrate another alternative embodiment where the shock absorber 20 includes a baffle 340 with a plurality of grooves 342 a, 342 b, 342 c, 342 d that extend helically along an inner surface 344 of the baffle 340. In the illustrated embodiment, the plurality of grooves 342 a, 342 b, 342 c, 342 d extend from an upper end 354 of the baffle 340 to a lower end 355 of the baffle 340; however, the plurality of grooves 342 a, 342 b, 342 c, 342 d may alternatively extend along only a part of the longitudinal length of the baffle 340. As shown in FIGS. 12-15, the baffle 340 extends annularly about the pressure tube 30 and is disposed radially between the pressure tube 30 and the reserve tube 36. However, it should be appreciated that the baffle 340 may alternatively extend less than 360 degrees about the pressure tube 30. For example, the baffle 340 may include a separation (i.e. a gap) that extends longitudinally from the upper end 354 to the lower end 355 of the baffle 340. In another alternative embodiment, the baffle 340 may include multiple separations that break the baffle 340 up into discrete sections that extend radially about only a portion of the pressure tube 30.

Together, grooves 342 a and 342 c define a baffle channel 356 in the form of a first helical passageway 358 a and a third helical passageway 358 c. In the illustrated embodiment, the first and third helical passageways 358 a, 358 c extend from the upper end 354 of the baffle 340 to the lower end 355 of the baffle 340 and radially between the outer cylindrical surface of the pressure tube 30 and the inner surface 344 of the baffle 340 in grooves 342 a and 342 c. However, it should be appreciated that the first and third helical passageways 358 a, 358 c may extend along only part of the longitudinal length of the baffle 340.

In accordance with this embodiment, the outer surface 346 of the baffle 340 is a smooth cylindrical surface and is spaced radially inward of the inner cylindrical surface of the reserve tube 36. A reservoir chamber 352 is disposed between the pressure tube 30 and the reserve tube 36 adjacent to the lower end 355 of the baffle 340 and between the outer surface 346 of the baffle 340 and the inner cylindrical surface of the reserve tube 36. Grooves 342 b and 342 d are disposed in fluid communication with the reservoir chamber 352 only. In other words, the grooves 342 b and 342 d are open to the reservoir chamber 352 at the lower end 355 of the baffle 340 and are closed at the upper end 354 of the baffle 340. Accordingly, grooves 342 b and 342 d also define part of the reservoir chamber 352 in the form of a second helical passageway 358 b and a fourth helical passageway 358 d. A liquid fluid such as an oil is contained in a lower region of the reservoir chamber 352 and a pressurized gas is contained in an upper portion of reservoir chamber 352.

The passageways 358 a, 358 b, 358 c, 358 d are non-linear and provide a tortuous fluid flow path along the inner surface 344 of the baffle 340. Because all of the passageways 358 a, 358 b, 358 c, 358 d have a helical shape, the passageways 358 a, 358 b, 358 c, 358 d have both a longitudinal component and a circumferential component. The plurality of grooves 342 a, 342 b, 342 c, 342 d and therefore the helical passageways 358 a, 358 b, 358 c, 358 d are radially spaced about the baffle 340 such that threads 360 a, 360 b, 360 c, 360 d are formed in the baffle 340 that extend radially inwardly from the baffle 340 between the plurality of grooves 342 a, 342 b, 342 c, 342 d. The inner surface 344 of the baffle 340 at the threads 360 a, 360 b, 360 c, 360 d contacts the outer cylindrical surface of the pressure tube 30 and supports the baffle 340 concentrically on the pressure tube 30. Because the inner surface 346 of the baffle 340 at the threads 360 a, 360 b, 360 c, 360 d contacts the outer cylindrical surface of the pressure tube 30, the helical passageways 358 a, 358 b, 358 c, 358 d defined by the plurality of grooves 342 a, 342 b, 342 c, 342 d are separate from one another (i.e., fluid flowing through the first helical passageway 358 a is isolated from fluid flowing through the second helical passageway 358 b along at least part of the longitudinal length of the baffle 340).

Both the first and third helical passageways 358 a and 358 c are disposed in fluid communication with at least one electromechanical valve assembly 126 and the reservoir chamber 352. Alternatively, the shock absorber 20 may include one electromechanical valve assembly for each of the first and third helical passageways 358 a and 358 c. When the at least one electromechanical valve assembly 126 is in the OPEN state, fluid flows through the first and third helical passageways 358 a and 358 c along flow direction F1. The second and fourth helical passageways 358 b and 358 d are disposed in fluid communication with only the reservoir chamber 352. The second and fourth helical passageways 358 b and 358 d are closed (i.e. not open) to the one or more electromechanical valve assemblies 126. Fluid in the reservoir chamber 352 flows in the opposite direction in the second and fourth helical passageways 358 b and 358 d along flow direction F2.

Fluid from the valve outlet 152 flows into the first and third helical passageways 358 a and 358 c and to the reservoir chamber 352. The baffle 340 may optionally include a clocking feature 364 that ensures proper positioning (i.e., indexing) of the baffle 340, where the first and third helical passageways 358 a and 358 c are circumferentially aligned with the valve outlet(s) 152 of the one or more electromechanical valve assemblies 126. By way of example and without limitation, the clocking feature 364 may be provided in the form of a notch in the upper end 354 of the baffle 340 that engages a tab on the rod guide assembly 50. In the illustrated example, the one or more electromechanical valve assemblies 126 are located in the rod guide assembly 50. However, other configurations are possible. For example, the one or more electromechanical valve assemblies 126 may be mounted externally on the reserve tube 36. Even though the one or more electromechanical valve assemblies 126 are external to the reserve tube 36, the inside passages of the one or more electromechanical valve assemblies 126 are disposed in fluid communication with the baffle channel 356 and the reservoir chamber 352. As a result, the one or more electromechanical valve assemblies 126 are operable to control fluid flow from the baffle channel 356 to the reservoir chamber 352.

Advantageously, the first and third helical passageways 358 a and 358 c defined by grooves 342 a and 342 c transport fluid from the electromechanical valve assembly 126 to the reservoir chamber 352 with minimal foaming (i.e., bubbling). The subject design minimizes the volume of the baffle channel 356. The subject design also maximizes the volume of the reservoir chamber 352 due to the added volume of second and fourth helical passageways 358 b and 358 d. In the example shown in FIGS. 12-15, the plurality of grooves 342 a, 342 b, 342 c, 342 d have a rectangular cross-sectional shape; however, it should be appreciated that other shapes are possible. In addition, it should be appreciated that the number of grooves and therefore the number of helical passageways may vary from the four grooves 342 a, 342 b, 342 c, 342 d and the four helical passageways 358 a, 358 b, 358 c, 358 d shown in the illustrated embodiment.

It should be appreciated that an alternative embodiment is possible where the embodiment of the shock absorber 20 includes a baffle that combines the features of the baffle 240 illustrated in FIGS. 9-11 and the baffle 340 illustrated in FIGS. 12-15. In accordance with this embodiment, the outer surface of the baffle may include helical passageways 258 a, 258 b, 258 c, 258 d along only a first portion of the longitudinal length of the baffle and the inner surface of the baffle may include helical passageways 358 a, 358 b, 358 c, 358 d along only a second portion of the longitudinal length of the baffle. Holes may be provided in the baffle so fluid can flow through the baffle and communicate between the helical passageways 258 a, 258 b, 258 c, 258 d on the outer surface of the baffle and the helical passageways 358 a, 358 b, 358 c, 358 d on the inner surface of the baffle. In accordance with this design, the inner surface of the baffle may be a smooth cylindrical surface along the first portion of the longitudinal length of the baffle and the outer surface of the baffle may be a smooth cylindrical surface along the second portion of the longitudinal length of the baffle.

FIGS. 16-19 illustrate another alternative embodiment where the shock absorber 20 includes a baffle 440 that has a plurality of inner grooves 442 a, 442 b, 442 c, 442 d and a plurality of outer grooves 443 a, 443 b, 443 c, 443 d. The plurality of inner grooves 442 a, 442 b, 442 c, 442 d extend longitudinally along an inner surface 444 of the baffle 440 and the plurality of outer grooves 443 a, 443 b, 443 c, 443 d extend longitudinally along an outer surface 446 of the baffle 440. The plurality of inner grooves 442 a, 442 b, 442 c, 442 d and a plurality of outer grooves 443 a, 443 b, 443 c, 443 d may extend from the upper end 454 of the baffle 440 to the lower end 456 of the baffle 440. Alternatively, the plurality of inner grooves 442 a, 442 b, 442 c, 442 d and a plurality of outer grooves 443 a, 443 b, 443 c, 443 d may extend along only part of the longitudinal length of the baffle 440. As shown in FIGS. 16-19, the baffle 440 extends annularly about the pressure tube 30 and is disposed radially between the pressure tube 30 and the reserve tube 36. However, it should be appreciated that the baffle 440 may alternatively extend less than 360 degrees about the pressure tube 30. For example, the baffle 440 may include a separation (i.e. a gap) that extends longitudinally from the upper end 454 to the lower end 455 of the baffle 440. In another alternative embodiment, the baffle 440 may include multiple separations that break the baffle 440 up into discrete sections that extend radially about only a portion of the pressure tube 30.

Together, the plurality of inner grooves 442 a, 442 b, 442 c, 442 d define a baffle channel 456 in the form of four inner helical passageways 458 a, 458 b, 458 c, 458 d. The inner helical passageways 458 a, 458 b, 458 c, 458 d extend helically along the baffle 440 from the upper end 454 of the baffle 440 to the lower end 455 of the baffle 440 and radially between the outer cylindrical surface of the pressure tube 30 and the inner surface 444 of the baffle 440 in the inner grooves 442 a, 442 b, 442 c, 442 d.

The plurality of outer grooves 443 a, 443 b, 443 c, 443 d define four outer helical passageways 459 a, 459 b, 459 c, 459 d. The outer helical passageways 459 a, 459 b, 459 c, 459 d extend helically along the baffle 440 from the upper end 454 of the baffle 440 to the lower end 456 of the baffle 440. A reservoir chamber 452 is disposed between the pressure tube 30 and the reserve tube 36 adjacent to the lower end 455 of the baffle 440. The outer helical passageways 459 a, 459 b, 459 c, 459 d are disposed in fluid communication with the reservoir chamber 452 only. In other words, the plurality of outer grooves 443 a, 443 b, 443 c, 443 d are open to the reservoir chamber 452 at the lower end 455 of the baffle 440 and are closed at the upper end 454 of the baffle 440. Accordingly, the outer helical passageways 459 a, 459 b, 459 c, 459 d form part of the reservoir chamber 452. A liquid fluid such as an oil is contained in a lower region of the reservoir chamber 452 and a pressurized gas is contained in an upper portion of reservoir chamber 452.

The plurality of inner grooves 442 a, 442 b, 442 c, 442 d and the plurality of outer grooves 443 a, 443 b, 443 c, 443 d and therefore the inner helical passageways 458 a, 458 b, 458 c, 458 d and the outer helical passageways 459 a, 459 b, 459 c, 459 d are non-linear and provide a tortuous fluid flow path along the inner surface 444 and the outer surface 446 of the baffle 440. Because all of the inner helical passageways 458 a, 458 b, 458 c, 458 d and the outer helical passageways 459 a, 459 b, 459 c, 459 d have a helical shape, the inner helical passageways 458 a, 458 b, 458 c, 458 d and the outer helical passageways 459 a, 459 b, 459 c, 459 d have both a longitudinal component and a circumferential component.

The plurality of inner grooves 442 a, 442 b, 442 c, 442 d and therefore the inner helical passageways 458 a, 458 b, 458 c, 458 d are radially spaced about the baffle 440 such that inner threads 460 a, 460 b, 460 c, 460 d are formed in the baffle 440 that extend radially inwardly from the baffle 440 between the plurality of inner grooves 442 a, 442 b, 442 c, 442 d. The inner surface 444 of the baffle 440 contacts the outer cylindrical surface of the pressure tube 30 at the threads 460 a, 460 b, 460 c, 460 d and supports the baffle 440 concentrically on the pressure tube 30. Because the inner surface 444 of the baffle 440 contacts the outer cylindrical surface of the pressure tube 30 at the threads 460 a, 460 b, 460 c, 460 d, the inner helical passageways 458 a, 458 b, 458 c, 458 d are separate from one another.

The plurality of outer grooves 443 a, 443 b, 443 c, 443 d and therefore the outer helical passageways 459 a, 459 b, 459 c, 459 d are radially spaced about the baffle 440 such that outer threads 461 a, 461 b, 461 c, 461 d are formed in the baffle 440 that extend radially inwardly from the baffle 440 between the plurality of outer grooves 443 a, 443 b, 443 c, 443 d. The outer surface 446 of the baffle 440 contacts the inner cylindrical surface of the reserve tube 36 at the threads 461 a, 461 b, 461 c, 461 d and supports the baffle 440 concentrically within the reserve tube 36. Because the outer surface 446 of the baffle 440 contacts the inner cylindrical surface of the reserve tube 36 at the threads 461 a, 461 b, 461 c, 461 d, the outer helical passageways 459 a, 459 b, 459 c, 459 d are separate from one another.

The electromechanical valve assembly 126 is disposed in fluid communication with each of the inner helical passageways 458 a, 458 b, 458 c, 458 d. When the electromechanical valve assembly 126 is in the OPEN state, fluid flows through the inner helical passageways 458 a, 458 b, 458 c, 458 d along flow direction F1 to the reservoir chamber 452, where the fluid then flows in the opposite direction in the outer helical passageways 459 a, 459 b, 459 c, 459 d along flow direction F2. Alternatively, the shock absorber 20 may include one electromechanical valve assembly for each of the inner helical passageways 458 a, 458 b, 458 c, 458 d.

Fluid from the valve outlet 152 flows into the inner helical passageways 458 a, 458 b, 458 c, 458 d and to the reservoir chamber 452. The baffle 440 may optionally include a clocking feature 464 that ensures proper positioning (i.e., indexing) of the baffle 440, where the inner helical passageways 458 a, 458 b, 458 c, 458 d are circumferentially aligned with the valve outlet(s) 152 of the one or more electromechanical valve assemblies 126. By way of example and without limitation, the clocking feature 464 may be provided in the form of a notch in the upper end 454 of the baffle 440 that engages a tab on the rod guide assembly 50. In the illustrated example, the one or more electromechanical valve assemblies 126 are located in the rod guide assembly 50. However, other configurations are possible. For example, the one or more electromechanical valve assemblies 126 may be mounted externally on the reserve tube 36. Even though the one or more electromechanical valve assemblies 126 are external to the reserve tube 36, the inside passages of the one or more electromechanical valve assemblies 126 are disposed in fluid communication with the baffle channel 456 and the reservoir chamber 452. As a result, the one or more electromechanical valve assemblies 126 are operable to control fluid flow from the baffle channel 456 to the reservoir chamber 452.

Advantageously, the separate inner helical passageways 458 a, 458 b, 458 c, 458 d defined by the plurality of inner grooves 442 a, 442 b, 442 c, 442 d transport fluid from the electromechanical valve assembly 126 to the reservoir chamber 452 with minimal foaming (i.e., bubbling). The subject design minimizes the volume of the baffle channel 456. The subject design also maximizes the volume of the reservoir chamber 452 due to the added volume of the outer grooves 443 a, 443 b, 443 c, 443 d. In the example shown in FIGS. 16-19, the plurality of inner grooves 442 a, 442 b, 442 c, 442 d and the plurality of outer grooves 443 a, 443 b, 443 c, 443 d have a rectangular cross-sectional shape; however, it should be appreciated that other shapes are possible. In addition, it should be appreciated that the number of inner and outer grooves and therefore the number of inner and outer helical passageways may vary from the four inner grooves 442 a, 442 b, 442 c, 442 d, four inner helical passageways 458 a, 458 b, 458 c, 458 d, four outer grooves 443 a, 443 b, 443 c, 443 d, and four outer helical passageways 459 a, 459 b, 459 c, 459 d shown in the illustrated embodiment.

FIGS. 20-23 illustrate another alternative embodiment where the shock absorber 20 includes a baffle 540 with a plurality of grooves 542 a, 542 b that extend in a non-linear, serpentine (zig-zag) path along an outer surface 546 of the baffle 540. In the illustrated embodiment, the plurality of grooves 542 a, 542 b extend from an upper end 554 of the baffle 540 to a lower end 555 of the baffle 540; however, the plurality of grooves 542 a, 542 b may alternatively extend along only a part of the longitudinal length of the baffle 540. As shown in FIGS. 20-23, the baffle 540 extends annularly about the pressure tube 30 and is disposed radially between the pressure tube 30 and the reserve tube 36. However, it should be appreciated that the baffle 540 may alternatively extend less than 360 degrees about the pressure tube 30. For example, the baffle 540 may include a separation (i.e. a gap) that extends longitudinally from the upper end 554 to the lower end 555 of the baffle 540. In another alternative embodiment, the baffle 540 may include multiple separations that break the baffle 540 up into discrete sections that extend radially about only a portion of the pressure tube 30.

In the illustrated embodiment, an inner surface 544 of the baffle 540 is a smooth cylindrical surface and is arranged in contact with the outer cylindrical surface of the pressure tube 30 to support the baffle 540 concentrically on the pressure tube 30. Alternatively, the inner surface 544 of the baffle 540 may be spaced radially outward of the outer cylindrical surface of the pressure tube 30 and the baffle 540 may be supported by the reserve tube 36.

Groove 542 a defines a baffle channel 556 in the form of a first non-linear passageway 558 a. In the illustrated embodiment, the first non-linear passageway 558 extends from the upper end 554 of the baffle 540 to the lower end 555 of the baffle 540 and radially between the inner cylindrical surface of the reserve tube 36 and the outer surface 546 of the baffle 540 in groove 542 a. However, it should be appreciated that the first non-linear passageway 558 a may extend along only part of the longitudinal length of the baffle 540. A reservoir chamber 552 is disposed between the pressure tube 30 and the reserve tube 36 adjacent to the lower end 555 of the baffle 540. Groove 542 b is disposed in fluid communication with the reservoir chamber 552 only. In other words, groove 542 b is open to the reservoir chamber 552 at the lower end 555 of the baffle 540 and is closed at the upper end 554 of the baffle 540. Accordingly, groove 542 b defines part of the reservoir chamber 552 in the form of a second non-linear passageway 558 b. A liquid fluid such as an oil is contained in a lower region of the reservoir chamber 552 and a pressurized gas is contained in an upper portion of reservoir chamber 552. In embodiments where the inner surface 544 of the baffle 540 is spaced radially outward of the outer cylindrical surface of the pressure tube 30, the space between the pressure tube 30 and the inner surface 544 of the baffle 540 may also form part of the reservoir chamber 552.

The non-linear shape of the first and second passageways 558 a and 558 b provide a tortuous fluid flow path along the outer surface 546 of the baffle 540. Because the first and second passageways 558 a, 558 b have a serpentine shape, the first and second passageways 558 a, 558 b have both a longitudinal component and a circumferential component. The plurality of grooves 542 a, 542 b and therefore the first and second passageways 558 a, 558 b are radially spaced about the baffle 540. The outer surface 546 of the baffle 540 between grooves 542 a, 542 b contacts the inner cylindrical surface of the reserve tube 36 to support the baffle 540 concentrically without the reserve tube 36. Because the outer surface 546 of the baffle 240 contacts the inner cylindrical surface of the reserve tube 36 between the grooves 542 a, 542 b, the first and second passageways 558 a, 558 b are separate from one another (i.e., fluid flowing through the first passageway 558 a is isolated from fluid flowing through the second passageway 558 b along at least part of the longitudinal length of the baffle 540).

In the illustrated embodiment, the first passageway 558 a is disposed in fluid communication with at least one electromechanical valve assembly 126 and the reservoir chamber 552. When the at least one electromechanical valve assembly 126 is in the OPEN state, fluid flows through the first passageway 558 a along flow direction F1. The second passageway 558 b is disposed in fluid communication with only the reservoir chamber 552. The second passageway 558 b is closed (i.e. not open) to the electromechanical valve assemblies 126. Fluid in the reservoir chamber 552 flows in the opposite direction in the second passageway 558 b along flow direction F2.

Transfer passage 562 extends through the baffle 540, communicating fluid from the valve outlet 152 to the first passageway 558 a. Fluid from the valve outlet 152 flows into the first passageway 558 a and to the reservoir chamber 552. The baffle 540 may optionally include a clocking feature 564 that ensures proper positioning (i.e., indexing) of the baffle 540, where the first passageway 558 a is circumferentially aligned with the valve outlet 152 of the one or more electromechanical valve assemblies 126. By way of example and without limitation, the clocking feature 564 may be provided in the form of a notch in the upper end 554 of the baffle 540 that engages a tab on the rod guide assembly 50. In the illustrated example, the one or more electromechanical valve assemblies 126 are located in the rod guide assembly 50. However, other configurations are possible. For example, the one or more electromechanical valve assemblies 126 may be mounted externally on the reserve tube 36. Even though the one or more electromechanical valve assemblies 126 are external to the reserve tube 36, the inside passages of the one or more electromechanical valve assemblies 126 are disposed in fluid communication with the baffle channel 556 and the reservoir chamber 552. As a result, the one or more electromechanical valve assemblies 126 are operable to control fluid flow from the baffle channel 556 to the reservoir chamber 552.

Advantageously, the first non-linear passageway 558 a defined by groove 542 a transports fluid from the electromechanical valve assembly 126 to the reservoir chamber 552 with minimal foaming (i.e., bubbling). The subject design minimizes the volume of the baffle channel 556. The subject design also maximizes the volume of the reservoir chamber 552 due to the added volume of second non-linear passageway 558 b. In the example shown in FIGS. 20-23, the plurality of grooves 542 a, 542 b have a rectangular cross-sectional shape; however, it should be appreciated that other shapes are possible. In addition, it should be appreciated that the number of grooves and therefore the number of non-linear passageways may vary from the two grooves 542 a, 542 b and the two non-linear passageways 558 a, 558 b shown in the illustrated embodiment. In yet another embodiment, both of the first and second non-linear passageways 558 a, 558 b may be disposed in fluid communication with the one or more electromechanical valve assemblies 126. In accordance with this embodiment, the inner surface 544 of the baffle 540 may be spaced radially outward of the outer cylindrical surface of the pressure tube 30 such that the reservoir chamber 552 is positioned radially between the pressure tube 30 and the baffle 540.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

What is claimed is:
 1. A shock absorber comprising: a pressure tube having an inner surface that defines a working chamber and an outer surface opposite the inner surface of the pressure tube; a piston assembly attached to a piston rod and slidably disposed within the pressure tube, the piston assembly dividing the working chamber into an upper working chamber and a lower working chamber; a reserve tube disposed around the pressure tube, the reserve tube having an inner surface that faces the pressure tube and an outer surface opposite the inner surface of the reserve tube; a baffle positioned radially between the pressure tube and the reserve tube to define a baffle channel and a reservoir chamber between the pressure tube and the reserve tube; and at least one valve positioned in fluid communication with the upper working chamber and the baffle channel for controlling fluid flow between the upper working chambers and the baffle channel, wherein the baffle channel includes a plurality of passageways that are defined by grooves in the baffle together with at least one of the outer surface of the pressure tube and the inner surface of the reserve tube, at least one of the plurality of passageways disposed in fluid communication with the at least one valve and the reservoir chamber, wherein when fluid flows through the at least one of the plurality of passageways in a first direction, fluid flows through another one of the plurality of passageways in a second opposite direction.
 2. The shock absorber of claim 1, wherein the plurality of passageways are non-linear and provide a tortuous fluid flow path along the baffle.
 3. The shock absorber of claim 2, wherein the grooves and the plurality of passageways extend from an upper end of the baffle to a lower end of the baffle.
 4. The shock absorber of claim 2, wherein the grooves extend helically along an inner surface of the baffle such that the grooves and the outer surface of the pressure tube cooperate to define the plurality of passageways.
 5. The shock absorber of claim 2, wherein the grooves extend helically along an outer surface of the baffle such that the grooves and the inner surface of the reserve tube cooperate to define the plurality of passageways.
 6. The shock absorber of claim 2, wherein the grooves include inner grooves and outer grooves and the plurality of passageways include inner passageways and outer passageways, the inner grooves extending helically along an inner surface of the baffle such that the inner grooves and the outer surface of the pressure tube cooperate to define the inner passageways, and the outer grooves extending helically along an outer surface of the baffle such that the outer grooves and the inner surface of the reserve tube cooperate to define the outer passageways.
 7. The shock absorber of claim 6, wherein the inner passageways are disposed in fluid communication with the at least one valve and the reservoir chamber and the outer passageways are disposed in fluid communication with only the reservoir chamber.
 8. The shock absorber of claim 2, wherein the grooves extend in a serpentine path along an outer surface of the baffle such that the grooves and the inner surface of the reserve tube cooperate to define the plurality of passageways.
 9. A shock absorber comprising: a pressure tube having an inner surface that defines a working chamber and an outer surface opposite the inner surface of the pressure tube; a piston assembly attached to a piston rod and slidably disposed within the pressure tube, the piston assembly dividing the working chamber into an upper working chamber and a lower working chamber; a reserve tube disposed around the pressure tube, the reserve tube having an inner surface that faces the pressure tube and an outer surface opposite the inner surface of the reserve tube; a baffle positioned radially between the pressure tube and the reserve tube to define a baffle channel and a reservoir chamber between the pressure tube and the reserve tube; and at least one valve positioned in fluid communication with the upper working chamber and the baffle channel for controlling fluid flow between the upper working chambers and the baffle channel, wherein the baffle channel includes a plurality of passageways that are defined by grooves in the baffle together with at least one of the outer surface of the pressure tube and the inner surface of the reserve tube, the plurality of passageways having a non-linear shape, at least one of the plurality of passageways disposed in fluid communication with the at least one valve and the reservoir chamber, wherein the at least one valve includes a first valve that is disposed in fluid communication with multiple passageways of the plurality of passageways.
 10. The shock absorber of claim 9, wherein the baffle channel and the plurality of passageways are positioned radially between the pressure tube and the baffle.
 11. The shock absorber of claim 9, wherein the baffle channel and the plurality of passageways are positioned radially between the reserve tube and the baffle.
 12. The shock absorber of claim 9, wherein the baffle is disposed in contact with and is supported by the pressure tube.
 13. The shock absorber of claim 9, wherein the baffle is disposed in contact with and is supported by the reserve tube.
 14. The shock absorber of claim 9, wherein the at least one valve is positioned between the piston rod and the reserve tube.
 15. The shock absorber of claim 9, wherein the at least one valve is positioned external to the reserve tube.
 16. A shock absorber comprising: a pressure tube having an inner surface that defines a working chamber and an outer surface opposite the inner surface of the pressure tube; a piston assembly attached to a piston rod and slidably disposed within the pressure tube, the piston assembly dividing the working chamber into an upper working chamber and a lower working chamber; a reserve tube disposed around the pressure tube, the reserve tube having an inner surface that faces the pressure tube and an outer surface opposite the inner surface of the reserve tube; a baffle positioned radially between the pressure tube and the reserve tube to define a baffle channel and a reservoir chamber between the pressure tube and the reserve tube; and at least one valve positioned in fluid communication with the upper working chamber and the baffle channel for controlling fluid flow between the upper working chambers and the baffle channel, wherein the baffle channel includes a plurality of passageways that are defined by grooves in the baffle together with at least one of the outer surface of the pressure tube and the inner surface of the reserve tube, at least one of the plurality of passageways disposed in fluid communication with the at least one valve and the reservoir chamber, wherein the plurality of passageways includes a first passageway that is disposed in fluid communication with the at least one valve and the reservoir chamber and a second passageway that is disposed in fluid communication with only the reservoir chamber.
 17. A shock absorber comprising: a pressure tube having an inner surface that defines a working chamber and an outer surface opposite the inner surface of the pressure tube; a piston assembly attached to a piston rod and slidably disposed within the pressure tube, the piston assembly dividing the working chamber into an upper working chamber and a lower working chamber; a reserve tube disposed around the pressure tube, the reserve tube having an inner surface that faces the pressure tube and an outer surface opposite the inner surface of the reserve tube; a baffle positioned radially between the pressure tube and the reserve tube to define a baffle channel and a reservoir chamber between the pressure tube and the reserve tube; and at least one valve positioned in fluid communication with the upper working chamber and the baffle channel for controlling fluid flow between the upper working chambers and the baffle channel, wherein the baffle channel includes a plurality of passageways that are defined by grooves in the baffle together with at least one of the outer surface of the pressure tube and the inner surface of the reserve tube, at least one of the plurality of passageways disposed in fluid communication with the at least one valve and the reservoir chamber, wherein the plurality of passageways includes a first passageway that is disposed in fluid communication with the at least one valve and the reservoir chamber and a second passageway that is disposed in fluid communication with the reservoir chamber and that is closed off from the at least one valve.
 18. A shock absorber comprising: a pressure tube having an inner surface that defines a working chamber and an outer surface opposite the inner surface of the pressure tube; a piston assembly attached to a piston rod and slidably disposed within the pressure tube, the piston assembly dividing the working chamber into an upper working chamber and a lower working chamber; a reserve tube disposed around the pressure tube, the reserve tube having an inner surface that faces the pressure tube and an outer surface opposite the inner surface of the reserve tube; a baffle positioned radially between the pressure tube and the reserve tube to define a baffle channel and a reservoir chamber between the pressure tube and the reserve tube; and at least one valve positioned in fluid communication with the upper working chamber and the baffle channel for controlling fluid flow between the upper working chambers and the baffle channel, wherein the baffle channel includes a plurality of passageways that are defined by grooves in the baffle together with at least one of the outer surface of the pressure tube and the inner surface of the reserve tube, the plurality of passageways having a non-linear shape, at least one of the plurality of passageways disposed in fluid communication with the at least one valve and the reservoir chamber, wherein the at least one valve includes multiple valves where there is one valve for each passageway in the plurality of passageways such that each passageway receives fluid from only one valve.
 19. A shock absorber comprising: a pressure tube having an inner surface that defines a working chamber and an outer surface opposite the inner surface of the pressure tube; a piston assembly attached to a piston rod and slidably disposed within the pressure tube, the piston assembly dividing the working chamber into an upper working chamber and a lower working chamber; a reserve tube disposed around the pressure tube, the reserve tube having an inner surface that faces the pressure tube and an outer surface opposite the inner surface of the reserve tube; a rod guide assembly attached to at least one of the reserve tube and the pressure tube, the piston rod extending through the rod guide assembly such that the rod guide assembly supports the piston rod; a baffle positioned radially between the pressure tube and the reserve tube to define a baffle channel and a reservoir chamber between the pressure tube and the reserve tube; and at least one valve positioned within the rod guide assembly and disposed in fluid communication with the upper working chamber and the baffle channel for controlling fluid flow between the upper working chambers and the baffle channel, wherein the baffle channel includes a plurality of passageways that are defined by grooves in the baffle together with at least one of the outer surface of the pressure tube and the inner surface of the reserve tube, the plurality of passageways having a non-linear shape to provide a tortuous fluid flow path along the baffle, at least one of the plurality of passageways disposed in fluid communication with the at least one valve and the reservoir chamber. 